Open Radar

 
NSArray of course has -objectAtIndex: and passing 0 will retrieve the first object. However, if the array contains 0 objects, an NSRangeException is raised (as expected and documented). However, NSArray also has -lastObject, which returns nil if the array is empty, rather than raising an exception. This method is a convenience to (presumably) help avoid querying -count and subtracting one just to find the last index. However, this same logic could be applied to reason for the existence of a -firstObject method as well.

- (id) firstObject {
	return [self count] == 0 ? nil : [self objectAtIndex:0];
}

Such a method would simplify code for getting the first object. I know this is perhaps an extremely minor perceived increase in convenience for developers, but the fact that -lastObject exists but no -firstObject complement does is strange (particularly to Cocoa newcomers), and the difference in behavior between -lastObject and -objectAtIndex: (nil object versus exception) is inconsistent and causes poor impedance matching. Please consider adding this API.